When disabling the SCO-Protocol but leaving Bluetooth on and connected to the car I don’t hear no more instruction through the phone speaker. I have to turn off Bluetooth to get instructions again. Is anyone of you experiencing the same behavior?

SCO protocol is for phonecall in car. We are using it for navigation instructions. If you turn it off then Android automatically switch into a2dp protocol-this you can hear in car system if you switch into media on car radio. Other voice channels doesnt affect sco functionality. For a2dp other channels can disable bluetooth on some devices. Thing is that bluetooth function was not tested enough(we dont have enough car systems for it-devices implementation is quite fragmented). I recommended to remove this function from 2.2 version before releasing...

I have the issue that the voice output is much too late if coming at all. I haven´t changed any settings thus operating with the default values. The car radio´s FM sound is mostly muted down when MF wants to tell me something but especially if it´s short speeches only they don´t "reach" the radio in time. Sometimes I have the feeleing that they are delayed but mostly I think that they are sent in "real time" but I just hear the rest of it becuase the beginning is not coming through althoug the FM sound is already muted. So in most cases the FM sound is muted only but no message comes from the phone. I have no idea whether this is a "bug" of the car radio or of the protocol or of MF.

Meanwhile I tried MFN with active bluetooth in two cars with similiar results:*) SCO enabled: I get instructions on the car radio but in a unsatisfying way (too late, too long interruption etc.). I don't know if these behaviours are car-related or not but anyhow, I would have no problem if I were able to hear instructions via the phone. But*) SCO disabled: no matter which sound output channel I choose, I get no more instructions by the phone speaker (only when turning off bluetooth generally).Because there has to be a bluetooth-connection to the car radio to be able to phone legally while driving, MFN in its current version for me is OF NO USE in a car.Question: Is there an older MFN-version available without this bluetooth-bug?

I sometimes still use (abuse) MNF by switching off the SCO protocol and using the external app "Mono Bluetooth Router". For me that works very good. No pause before and after the message, and no somewhat late instructions.

I had installed Mono BT Router and connected it to the car. As soon as it was connected the radio station was muted immediately. So I haven´t even tested whether there would be any sound from the phone. Is there any specific setting I need to apply to prevent the permanent muting of the car radio?

I know a little bit about the several bluetooth protocols but I'm no expert whatsoever on the implementation in the different apps or in Navigator.

There is a difference between SCO and A2DP within the bluetooth protocols (and there are more).

SCO is only for voice data. So for instructions it seems fine. However, I think this is the reason that you get the "incoming phone call" message on your radio when you use it in Navigator. I have that both in Navigator as in the other app where I select SCO (MNF) or phone output (other app).

A2DP is for media for either hifi mono or hifi stereo sound. The other app works fine on "media" without the disturbing and sometimes delaying "incoming phone .." message.

But not in all cars as mentioned above.

There are numerous posts on the web where you can find that a bluetooth set in the car works fine with phone calls, but not with media. Almost all cars are A2DP compliant as well today, but it simply doesn't seem to work always.

Actually the "MonoBluetooth Router" apk is not for connection to car kits but to "mono bluetooth headsets" but that worked OK for me in previous Navigator versions before the bluetooth implementation. And it still comes in handy in some cars (as mentioned above). I think it simply "grabs" all kinds of audio data streams and sends it over the same bluetooth output, but that's a guess.

I'm not exactly sure whether SCO is the best way to handle this w.r.t. to the "incoming phone call" message. If I don't use SCO, but via media on the "Mono bluetooth router" it almost always functions.

That is with my phone: Samsung S5 mini Android 5.1.1. But I'm afraid it varies per phone.

(Note: my own car doesn't have bluetooth, but will have it in 3-4 days. I'm very curious)